Pathogen Inactivation Systems Research Articles

Sterility Testing of Platelets Concentrate Within Quality Control: Experiences and Opportunities to Extend the Application

Abstract Despite numerous measures, bacterial sepsis associated with the transfusion remains a major threat. The incidence of septic events induced by platelets transfusion is approximately 10 times higher than with transfused red blood cells due to their storage temperature. This caused new Standard that implements the methods for the detection and reduction of bacteria in the platelet concentrates (PC). The aim is to consider the possibility of wider application of this tests in order to extend the shelf-life of PC. Sterility testing of PC is done once or twice per month using BacT/Alert BPA and BacT/Alert BPN bottles. If positive, all products from the initial unit were tested to confirm or deny the status. During six years period, 67236 PC units were made and 872 of them were tested. Only two were found initially positive. After testing the other products from the same initial unit, results were negative so, final results proclaimed false positive. Pretransfusion bacterial detection is an important potential method for reducing the risk of bacteriemia and transfusion-associated septic reactions. In addition to routine measures, Mirasol PRT pathogen inactivation system, could be included. This allows certain amount of PC to be inactivated during the first 32 hours. Untreated PC units would be stored in standard conditions and for given time (three days) potentially present bacteria would reach a detectable level. This way the quantity of samples for sterility testing could be reduced, taking only 2 ml of each of four units of PC. Samples would be planted at the same vial-aerobic bottle, which would also, double the capacity in BacT/Alert 3D automated system.

Inactivation of SARS-CoV-2 infectivity in platelet concentrates or plasma following treatment with ultraviolet C light or with methylene blue combined with visible light.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unlikely to be a major transfusion-transmitted pathogen, however, convalescent plasma is a treatment option used in some regions. The risk of transfusion-transmitted infections can be minimised by implementing Pathogen Inactivation (PI), such as THERAFLEX MB-Plasma and THERAFLEX UV-Platelets systems. Here we examined the capability of these PI systems to inactivate SARS-CoV-2. SARS-CoV-2 spiked plasma units were treated using the THERAFLEX MB-Plasma system in the presence of methylene blue (~0.8 μmol/L; visible light doses: 20, 40, 60 and 120 [standard] J/cm2 ). SARS-CoV-2 spiked platelet concentrates (PCs) were treated using the THERAFLEX UV-Platelets system (UVC doses: 0.05, 0.10, 0.15 and 0.20 [standard] J/cm2 ). Samples were taken prior to the first and after each illumination dose and viral infectivity was assessed using an immunoplaque assay. Treatment of spiked plasma with the THERAFLEX MB-Plasma system resulted in an average ≥5.03 log10 reduction in SARS-CoV-2 infectivity at one third (40 J/cm2 ) of the standard visible light dose. For the platelet concentrates (PCs), treatment with the THERAFLEX UV-Platelets system resulted in an average ≥5.18 log10 reduction in SARS-CoV-2 infectivity at the standard UVC dose (0.2 J/cm2 ). SARS-CoV-2 infectivity was reduced in plasma and platelets following treatment with the THERAFLEX MB-Plasma and THERAFLEX UV-Platelets systems, to the limit of detection, respectively. These PI technologies could therefore be an effective option to reduce the risk of transfusion-transmitted emerging pathogens. This article is protected by copyright. All rights reserved.

Hepatitis E virus is effectively inactivated by methylene blue plus light treatment.

Photodynamic treatment with methylene blue (MB) and visible light is a well-established pathogen inactivation system for human plasma. This technique is routinely used in different countries. MB/light treatment was shown to inactivate several transfusion-transmittable viruses, but its efficiency for the inactivation of the quasi-enveloped hepatitis E virus (HEV) has not yet been investigated. Plasma units were spiked with cell culture-derived HEV and treated with the THERAFLEX MB-Plasma system using various light doses (30, 60, 90, and 120 J/cm2 ). HEV titers in pre- and post-treatment samples were determined by virus titration and a large-volume plating assay to improve the detection limit of the virus assay. THERAFLEX MB-Plasma efficiently inactivated HEV in human plasma. Even the lowest light dose of 30 J/cm2 inactivated HEV down to the limit of detection, with a mean log reduction factor of greater than 2.4 for the total process. Our study demonstrates that the THERAFLEX MB-Plasma system effectively inactivates HEV in human plasma.

Expanded validation of the effect and quality of a pathogen inactivation system based on riboflavin photochemistry on platelet bacterial contamination

BackgroundBacterial contamination still poses serious challenges to blood safety. Platelets have the highest bacterial contamination risk of all blood components.MethodsTwenty units of manual platelets were prepared from blood donated by our hospital, which were inoculated with Staphylococcus aureus and Escherichia coli suspensions. The riboflavin sodium phosphate solution was added into platelets, adjusted to a final concentration of 160 μmol/L. Platelets added into an illumination bag and placed in the inactivation system for riboflavin photochemistry at various doses. The inactivation effect of bacteria was evaluated on a Columbia blood agar plate by the plate counting method. Meanwhile, the blood routine, blood gas analysis, platelet aggregation test, and thromboelastogram of platelets before and after treatment were detected to evaluate the changes of platelet quality after treatment.Resultsthe inactivation effect of S. aureus and E. coli at the inactivation dose (16.9 J/cm2) could reach more than 4 logs. After treatment at 16.9 J/cm2, the blood routine results showed that the platelet count was significantly different (P<0.05), and the blood gas analysis showed that the oxygen partial pressure (pO2) and lactic acid concentration (cLac) were also significantly different (P<0.05). After 16.9 J/cm2 treatment, there was a significant difference between Arachidonic acid (AA) and Collagen (Cog) activator groups in the platelet aggregation experiment (P<0.05), but there was no significant difference in the main thrombelastogram (TEG) parameters (R value, K value, angle value, MA value) after treatment (P>0.05).ConclusionsThe inactivation effect of this set of blood component pathogen inactivation system on platelet bacterial contamination could be considered to meet actual clinical needs, with the inactivation treatment having little impact on platelet function.

Antioxidant power measurement in platelet concentrates treated by two pathogen inactivation systems in different blood centres.

The antioxidant power measurement can be useful to validate the execution of the pathogen inactivation treatment of platelet concentrates. The aim of this study is to evaluate the technology on different blood preparations including INTERCEPT and Mirasol treatments that are in routine use in Belgium and Luxemburg. The antioxidant power measurement was tested on 78 apheresis platelet concentrates and 54 pools of buffy-coats-derived platelet concentrates before and after INTERCEPT treatment. In addition, 100 Reveos platelet pools were tested before and after Mirasol treatment. The antioxidant power was quantified electrochemically using disposable devices and was expressed as equivalent ascorbic acid concentration. Mean results for apheresis platelet concentrates were of 90±14 and 35±10µmol/l eq. ascorbic acid before and after INTERCEPT treatment, respectively. The mean results for pools of buffy-coats-derived platelet concentrates were of 81±10 and 29±4eq. µmol/l ascorbic acid before and after INTERCEPT treatment, respectively. For buffy-coats-derived platelet concentrates treated by Mirasol technology, the mean results were of 98±11 and 32±10µmol/l eq. ascorbic acid before and after illumination, respectively. The antioxidant power significantly decreases with pathogen inactivation treatments for platelet concentrates treated by INTERCEPT or Mirasol technologies.

Hepatitis E virus is effectively inactivated in platelet concentrates by ultraviolet C light

As previous investigations have shown, THERAFLEX UV-Platelets, a UVC-based pathogen inactivation (PI) system, is effective against non-enveloped transfusion-relevant viruses such as hepatitis A virus (HAV), which are insensitive to most PI treatments for blood products. This study investigated the PI efficacy of THERAFLEX UV-Platelets against HEV in platelet concentrates (PCs). Buffy coat-derived PCs in additive solution were spiked with cell culture-derived HEV and treated with the THERAFLEX UV-Platelets system using various doses of UVC (0·05, 0·10, 0·15 and 0·20 (standard) J/cm2 ). Titres of infectious virus in pre- and post-treatment samples were determined using a large-volume plating assay to improve the detection limit of the virus assay. THERAFLEX UV-Platelets dose-dependently inactivated HEV in PCs. The standard UVC dose inactivated the virus to below the limit of detection, corresponding to a mean log reduction of greater than 3·5. Our study demonstrates that the THERAFLEX UV-Platelets system effectively inactivates HEV in PCs.

Inactivation of three emerging viruses – severe acute respiratory syndrome coronavirus, Crimean–Congo haemorrhagic fever virus and Nipah virus – in platelet concentrates by ultraviolet C light and in plasma by methylene blue plus visible light

BackgroundEmerging viruses like severe acute respiratory syndrome coronavirus (SARS‐CoV), Crimean–Congo haemorrhagic fever virus (CCHFV) and Nipah virus (NiV) have been identified to pose a potential threat to transfusion safety. In this study, the ability of the THERAFLEX UV‐Platelets and THERAFLEX MB‐Plasma pathogen inactivation systems to inactivate these viruses in platelet concentrates and plasma, respectively, was investigated.Materials and methodsBlood products were spiked with SARS‐CoV, CCHFV or NiV, and then treated with increasing doses of UVC light (THERAFLEX UV‐Platelets) or with methylene blue (MB) plus increasing doses of visible light (MB/light; THERAFLEX MB‐Plasma). Samples were taken before and after treatment with each illumination dose and tested for residual infectivity.ResultsTreatment with half to three‐fourths of the full UVC dose (0·2 J/cm2) reduced the infectivity of SARS‐CoV (≥3·4 log), CCHFV (≥2·2 log) and NiV (≥4·3 log) to the limit of detection (LOD) in platelet concentrates, and treatment with MB and a fourth of the full light dose (120 J/cm2) decreased that of SARS‐CoV (≥3·1 log), CCHFV (≥3·2 log) and NiV (≥2·7 log) to the LOD in plasma.ConclusionOur study demonstrates that both THERAFLEX UV‐Platelets (UVC) and THERAFLEX MB‐Plasma (MB/light) effectively reduce the infectivity of SARS‐CoV, CCHFV and NiV in platelet concentrates and plasma, respectively.

Metabolomics study of platelet concentrates photochemically treated with amotosalen and UVA light for pathogen inactivation

The risk of bacterial contamination and the deterioration of platelet (PLT) quality limit the shelf-life of platelet concentrates (PCs). The INTERCEPT pathogen inactivation system reduces the risk of pathogen transmission by inhibiting nucleic acid replication using a combination of a photo-reactive compound and UVA illumination. The goal of this study was to investigate the effects the INTERCEPT system has on the PLT metabolome and metabolic activity. Paired units of buffy coat-derived PCs were generated using a pool and split strategy (n = 8). The paired PCs were either treated with the INTERCEPT system or left untreated. Samples were collected on Days 1, 2, 4, and 7 of storage. Ultra-performance chromatography coupled with time-of-flight mass spectrometry was used to analyze the extra- and intracellular metabolomes. Constraint-based metabolic modeling was then used to predict the metabolic activity of the stored PLTs. A relatively large number of metabolites in the extracellular environment were depleted during the processing steps of the INTERCEPT system, in particular, metabolites with hydrophobic functional groups, including acylcarnitines and lysophosphatidylcholines. In the intracellular environment, alterations in glucose and glycerophospholipid metabolism and decreased levels of 2-hydroxyglutarate were observed following the INTERCEPT treatment. Untargeted metabolomics analysis revealed residual amotosalen dimers present in the treated PCs. Systems-level analysis of PLT metabolism indicated that the INTERCEPT system does not have a significant impact on the PLT energy metabolism and nutrient utilization. The INTERCEPT system significantly alters the metabolome of the stored PCs without significantly influencing PLT energy metabolism.

Electrically heatable carbon nanotube point-of-use filters for effective separation and in-situ inactivation of Legionella pneumophila

Despite municipal chlorination and secondary disinfection, opportunistic waterborne pathogens (e.g., Legionella spp.) persist in public and private water distribution systems. As a potential source of healthcare-acquired infections, this warrants development of novel pathogen removal and inactivation systems. In this study, electrically heatable carbon nanotube (CNT) point-of-use (POU) filters have been designed to remove and inactivate Legionella pneumophila in water. The CNT/polymer composite membranes effectively removed Legionella (>99.99%) (i.e., below detection limit) and were able to inactive them on the membrane surface at 100% efficiency within 60 s using ohmic heating at 20 V. The novel POU filters could be used as a final barrier to provide efficient rejection of pathogens and thereby simultaneously eliminate microorganisms in public and private water supplies.

Bacterial inactivation of platelet concentrates with the THERAFLEX UV-Platelets pathogen inactivation system.

The THERAFLEX UV-Platelets system (Maco Pharma) uses ultraviolet C (UVC) light for pathogen inactivation (PI) of platelet concentrates (PCs) without any additional photoactive compound. The aim of the study was to systematically investigate bacterial inactivation with this system under conditions of intended use. The robustness of the system was evaluated by assessing its capacity to inactivate high concentrations of different bacterial species in accordance with World Health Organization guidelines. The optimal use of the PI system was explored in time-to-treatment experiments by testing its ability to sterilize PCs contaminated with low levels of bacteria on the day of manufacture (target concentration, 100 colony-forming units/unit). The bacteria panel used for spiking experiments in this study included the World Health Organization International Repository Platelet Transfusion Relevant Reference Strains (n = 14), commercially available strains (n = 13), and in-house clinical isolates (n = 2). Mean log reduction factors after UVC treatment ranged from 3.1 to 7.5 and varied between different strains of the same species. All PCs (n = 12/species) spiked with up to 200 colony-forming units/bag remained sterile until the end of storage when UVC treated 6 hours after spiking. UVC treatment 8 hours after spiking resulted in single breakthrough contaminations with the fast-growing species Escherichia coli and Streptococcus pyogenes. The UVC-based THERAFLEX UV-Platelets system efficiently inactivates transfusion-relevant bacterial species in PCs. The comprehensive data from this study may provide a valuable basis for the optimal use of this UVC-based PI system.

Ultraviolet-Based Pathogen Inactivation Systems: Untangling the Molecular Targets Activated in Platelets.

Transfusions of platelets are an important cornerstone of medicine; however, recipients may be subject to risk of adverse events associated with the potential transmission of pathogens, especially bacteria. Pathogen inactivation (PI) technologies based on ultraviolet illumination have been developed in the last decades to mitigate this risk. This review discusses studies of platelet concentrates treated with the current generation of PI technologies to assess their impact on quality, PI capacity, safety, and clinical efficacy. Improved safety seems to come with the cost of reduced platelet functionality, and hence transfusion efficacy. In order to understand these negative impacts in more detail, several molecular analyses have identified signaling pathways linked to platelet function that are altered by PI. Because some of these biochemical alterations are similar to those seen arising in the context of routine platelet storage lesion development occurring during blood bank storage, we lack a complete picture of the contribution of PI treatment to impaired platelet functionality. A model generated using data from currently available publications places the signaling protein kinase p38 as a central player regulating a variety of mechanisms triggered in platelets by PI systems.

Refrigeration, cryopreservation and pathogen inactivation: an updated perspective on platelet storage conditions

Conventional storage of platelet concentrates limits their shelf life to between 5 and 7 days due to the risk of bacterial proliferation and the development of the platelet storage lesion. Cold storage and cryopreservation of platelets may facilitate extension of the shelf life to weeks and years, and may also provide the benefit of being more haemostatically effective than conventionally stored platelets. Further, treatment of platelet concentrates with pathogen inactivation systems reduces bacterial contamination and provides a safeguard against the risk of emerging and re-emerging pathogens. While each of these alternative storage techniques is gaining traction individually, little work has been done to examine the effect of combining treatments in an effort to further improve product safety and minimize wastage. This review aims to discuss the benefits of alternative storage techniques and how they may be combined to alleviate the problems associated with conventional platelet storage.

Evaluation of bacterial inactivation in random donor platelets and single-donor apheresis platelets by the INTERCEPT blood system.

BACKGROUND:Blood transfusion of contaminated components is a potential source of sepsis by a wide range of known and unknown pathogens. Collection mechanism and storage conditions of platelets make them vulnerable for bacterial contamination. Several interventions aim to reduce the transfusion of contaminated platelet units; however, data suggest that contaminated platelet transfusion remains very common.AIM:A pathogen inactivation system, “INTERCEPT”, to inactivate bacteria in deliberately contaminated platelet units was implemented and evaluated.MATERIALS AND METHODS:Five single-donor platelets (SDP) and five random donor platelets (RDP) were prepared after prior consent of donors. Both SDP and RDP units were deliberately contaminated by stable stock ATCC Staphylococcus aureus and Escherichia coli, respectively, with a known concentration of stock culture. Control samples were taken from the infected units and bacterial concentrations were quantified. The units were treated for pathogen inactivation with the INTERCEPT (Cerus Corporation, Concord, CA) Blood system for platelets (Amotosalen/UVA), as per the manufacturer's instructions for use. Post illumination, test samples were analyzed for any bacterial growth.RESULTS:Post-illumination test samples did not result in any bacterial growth. A complete reduction of >6 log10 S. aureus in SDP units and >6 log10 Escherichia coli in RDP units was achieved.CONCLUSION:The INTERCEPT system has been shown to be very effective in our study for bacterial inactivation. Implementation of INTERCEPT may be used as a mitigation against any potential bacterial contamination in platelet components.

Bacterial testing of platelets - has it prevented transfusion-transmitted bacterial infections in Australia?

Australia introduced bacterial contamination screening (BCS) for platelet components in April 2008. This study presents analysis performed to assess the efficacy of testing. Seven-day aerobic and anaerobic culture is performed using the BacT/ALERT 3D system. Following an initial machine positive (IMP) flag, all associated components are recalled, and/or clinicians treating already transfused patients are notified. IMPs are categorized as 'machine false positive', 'confirmed positive' or 'indeterminate' depending on culture results of initial and repeat samples. Between 2010 and 2012, 1·1% of platelet donations tested IMP; since 2013, this rate has fallen to 0·6% through improved instrument management, reducing false-positive IMPs but maintaining sensitivity for cultures yielding bacterial growth. On average, 66% of confirmed positive and indeterminate platelet units had been transfused at the time of detection. The majority (95%) of these grew Propionibacterium sp., a slow-growing organism that rarely causes sepsis in the transfusion setting. The incidence of reported transfuion-transmitted bacterial infection (TTBI) has fallen since the introduction of BCS, with a 4·2-fold [0·5, 28·2] lower rate from platelets. BCS has been successful in detecting platelet units containing pathogenic bacteria. The incidence of TTBI from platelets has fallen since the introduction of BCS, but the risk has not been eliminated due to rare false-negative results. In the absence of a pathogen inactivation system for red blood cells, BCS provides 'surrogate' testing of red blood cells from which platelets have been manufactured.

Inactivation of Zika virus in platelet components using amotosalen and ultraviolet A illumination.

Concerned over the risk of Zika virus (ZIKV) transfusion transmission, public health agencies recommended the implementation of mitigation strategies for its prevention. Those strategies included the use of pathogen inactivation for the treatment of plasma and platelets. The efficacy of amotosalen/ultraviolet A to inactivate ZIKV in plasma had been previously demonstrated, and the efficacy of inactivation in platelets with the same technology was assumed. These studies quantify ZIKV inactivation in platelet components using amotosalen/ultraviolet A. Platelet components were spiked with ZIKV, and ZIKV infectious titers and RNA loads were measured by cell culture-based assays and real-time polymerase chain reaction in spiked platelet components before and after photochemical treatment using amotosalen/ultraviolet A. The mean ZIKV infectivity titers and RNA loads in platelet components before inactivation were either 4.9 log10 plaque forming units per milliliter, or 4.4 log10 50% tissue culture infective dose per milliliter and 7.5 log10 genome equivalents per milliliter, respectively. No infectivity was detected immediately after amotosalen/ultraviolet A treatment. No replicative virus remained after treatment, as demonstrated by multiple passages on Vero cell cultures; and ZIKV RNA was not detected from the first passage after inactivation. Additional experiments in this study demonstrated efficient inactivation to the limit of detection in platelets manufactured in 65% platelet additive solution, 35% plasma, or 100% plasma. As previously demonstrated for plasma, robust levels of ZIKV inactivation were achieved in platelet components. With inactivation of higher levels of ZIKV than those reported in asymptomatic, RNA-reactive blood donors, the pathogen-inactivation system using amotosalen/ultraviolet A offers the potential to mitigate the risk of ZIKV transmission by plasma and platelet transfusion.

Amustaline (S-303) treatment inactivates high levels of Zika virus in red blood cell components.

The potential for Zika virus (ZIKV) transfusion-transmission (TT) has been demonstrated in French Polynesia and Brazil. Pathogen inactivation (PI) of blood products is a proactive strategy to inactivate TT pathogens including arboviruses. Inactivation of West Nile, dengue, Zika, and chikungunya viruses was previously demonstrated by photochemical treatment with amotosalen and ultravioletA (UVA) illumination. In this study, we evaluated ZIKV inactivation in red blood cell (RBC) components by a chemical approach that uses amustaline (S-303) and glutathione (GSH). RBC components were spiked with a high titer of ZIKV. Viral titers (infectivity) and ZIKV RNA loads (reverse transcription-polymerase chain reaction) were measured in spiked RBCs before and after S-303 and GSH treatment and confirmed using repetitive passages in cell culture. A mock-treated arm validated the approach by demonstrating stability of the virus (infectivity and RNA load) during the process. The mean ZIKV infectivity titer and RNA load in RBCs were 5.99±0.2 log 50% tissue culture infectious dose (TCID50 )/mL and 7.75±0.16 log genomic equivalents/mL before inactivation. No infectivity was detected immediately after S-303 and GSH treatment and after five serial passages in cell culture. Complete ZIKV inactivation of more than 5.99 log TCID50 /mL in RBCs was achieved using S-303 and GSH at levels higher than those found in asymptomatic ZIKV-infected blood donors. Therefore, the S-303 and GSH PI system is promising for mitigating the risk of ZIKV TT.

Detection, fate and inactivation of pathogenic norovirus employing settlement and UV treatment in wastewater treatment facilities

It is accepted that discharged wastewaters can be a significant source of pathogenic viruses in receiving water bodies contributing to pollution and may in turn enter the human food chain and pose a risk to human health, thus norovirus (NoV) is often a predominant cause of gastroenteritis globally. Working with NoV poses particular challenges as it cannot be readily identified and detection by molecular methods does not assess infectivity. It has been proposed that the infectivity of NoV may be modelled through the use of an alternative virus; F-specific RNA (FRNA) bacteriophages; GA genotype and other FRNA bacteriophages have been used as a surrogate in studies of NoV inactivation.This study investigated the efficiency of novel pulsed ultraviolet irradiation and low pressure ultraviolet irradiation as a potential pathogen inactivation system for NoV and FRNA bacteriophage (GA) in secondary treated wastewaters. The role of UV dose and the impact of suspended solids concentration on removal efficiency were also examined. The study also investigated the role of settlement processes in wastewater treatment plants in removing NoV. While NoV inactivation could not be determined it was found that at a maximum UV dose of 6.9J/cm2 (6900mJ/cm2) an average 2.4 log removal of FRNA bacteriophage (GA) was observed; indicating the potential need for high UV doses to remove NoV if FRNA bacteriophage prove a suitable indicator for NoV. The study found that increasing concentrations of suspended solids impacted on PUV efficiency however, it appears the extent of the impact may be site specific. Furthermore, the study found that settlement processes can play a significant role in the removal of FRNA bacteriophage, thus potentially NoV.

Blood-Borne Pathogens: A Canadian Blood Services Centre for Innovation Symposium.

Testing donations for pathogens and deferring selected blood donors have reduced the risk of transmission of known pathogens by transfusion to extremely low levels in most developed countries. Protecting the blood supply from emerging infectious threats remains a serious concern in the transfusion medicine community. Transfusion services can employ indirect measures such as surveillance, hemovigilance, and donor questioning (defense), protein-, or nucleic acid based direct testing (detection), or pathogen inactivation of blood products (destruction) as strategies to mitigate the risk of transmission-transmitted infection. In the North American context, emerging threats currently include dengue, chikungunya, and hepatitis E viruses, and Babesia protozoan parasites. The 2003 SARS and 2014 Ebola outbreaks illustrate the potential of epidemics unlikely to be transmitted by blood transfusion but disruptive to blood systems. Donor-free blood products such as ex vivo generated red blood cells offer a theoretical way to avoid transmission-transmitted infection risk, although biological, engineering, and manufacturing challenges must be overcome before this approach becomes practical. Similarly, next generation sequencing of all nucleic acid in a blood sample is currently possible but impractical for generalized screening. Pathogen inactivation systems are in use in different jurisdictions around the world, and are starting to gain regulatory approval in North America. Cost concerns make it likely that pathogen inactivation will be contemplated by blood operators through the lens of health economics and risk-based decision making, rather than in zero-risk paradigms previously embraced for transfusable products. Defense of the blood supply from infectious disease risk will continue to require innovative combinations of surveillance, detection, and pathogen avoidance or inactivation.

Paired comparison of methylene blue- and amotosalen-treated plasma and cryoprecipitate.

Cryoprecipitate is used in the treatment of patients with acquired hypofibrinogenaemia. Studies have not directly compared cryoprecipitate produced following pathogen inactivation (PI) of fresh-frozen plasma (FFP) using different systems. The effects of methylene blue (MB) and amotosalen (AS) PI systems on the quality of FFP and cryoprecipitate were investigated in a paired study. Seven group A and 7 group O pools of plasma were prepared and split into individual units and rapidly frozen to produce FFP. Units of FFP were thawed and either PI treated with MB or amotosalen, or left untreated (control). Samples of FFP along with the corresponding cryoprecipitate were tested for a range of coagulation factors, thrombin generation (TGT) and rotational thromboelastometry (ROTEM). AS-FFP showed a smaller decrease following treatment for most coagulation factors analysed than MB-FFP, except fibrinogen (antigen) and factor VII, partly due to lower volume losses. There was no significant difference between treatment methods for fibrinogen content of cryoprecipitate with treated units meeting current UK specification, or TGT and ROTEM parameters studied. MB-cryo contained a significantly higher content of FVIII and lower content of FXIII when compared to AS-cryo, with no difference in fibrinogen activity.

Treatment of Platelet Concentrates with the Mirasol Pathogen Inactivation System Modulates Platelet Oxidative Stress and NF-κB Activation

Background: Pathogen inactivation (PI) technologies for platelets aim to improve transfusion safety by preventing the replication of contaminating pathogens. However, as a consequence of treatment, aspects of the platelet storage lesion are amplified. Mirasol treatment also affects platelet signal transduction and apoptotic protein expression. The aim of this study was to examine the effect of Mirasol treatment on the generation of reactive oxygen species (ROS) and subsequent oxidative stress. Methods: Pooled platelet concentrates were prepared in platelet-additive solution (70% SSP+ / 30% plasma). ABO-matched platelets were pooled and split, and treated with the Mirasol system (TerumoBCT) or left untreated as a control. Platelet samples were tested on day 1, 5, and 7 post-collection. Results: Mirasol-treated platelets had increased formation of ROS by day 5 of storage. Oxidative damage, in the form of protein carbonylation, was higher in Mirasol-treated platelets, whilst no effect on nitrotyrosine formation or lipid peroxidation was detected. The NF-κB signaling pathway was also activated in Mirasol-treated platelets, with increased expression and phosphorylation of NF-κB p65 and IκBa. Conclusion: These data demonstrate that Mirasol-treated platelets produce more ROS and display protein alterations consistent with oxidative damage.